Apparatus for melting adhesives or crack-sealing materials within a propane, electric, or diesel powered melter, and for applying such adhesives or materials to roadway surfaces, are well known in the art. Exemplary patents disclosing such apparatus or systems comprise U.S. Pat. No. 6,663,016 which issued to Bien on Dec. 16, 2003, U.S. Pat. No. 6,109,826 which issued to Mertes on Aug. 29, 2000, U.S. Pat. No. 6,049,658 which issued to Schave et al. on Apr. 11, 2000, U.S. Pat. No. 5,974,227 which issued to Schave on Oct. 26, 1999, U.S. Pat. No. 5,967,375 which issued to Barnes on Oct. 19, 1999, U.S. Pat. No. 5,832,178 which issued to Schave on Nov. 3, 1998, U.S. Pat. No. 4,887,908 which issued to Montgomery et al. on Dec. 19, 1989, U.S. Pat. No. 4,887,741 which issued to Downing on Dec. 19, 1989, U.S. Pat. No. 4,859,073 which issued to Howseman, Jr. et al. on Aug. 22, 1989, U.S. Pat. No. 4,692,028 which issued to Schave on Sep. 8, 1987, U.S. Pat. No. 4,620,645 which issued to Hale on Nov. 4, 1986, U.S. Pat. No. 4,159,877 which issued to Jacobson et al. on Jul. 3, 1979, and U.S. Pat. No. 3,841,527 which issued to Von Roeschlaub on Oct. 15, 1974.
U.S. Pat. No. 6,109,826 issued to Mertes on Aug. 29, 2000, is one example of a prior art melter and applicator system which was apparently state-of-the-art at the time that such patent issued in connection with the application of materials to be dispensed in connection with road paving or sealing operations, however, as can be appreciated from FIG. 1 of the application drawings, which corresponds to FIG. 1 of the noted patent, the system of Mertes embodies some fundamental operational problems. In accordance with the system of Mertes, a bin 26 is disclosed for containing the particular materials to be melted. More particularly, the bin 26 is provided with an access cover 28 so as to permit solidified paving materials, such as, for example, asphalt bricks to be loaded into the bin 26. An agitator 52 is rotatably disposed within the bottom portion of the bin 26 so as to constantly mix the heated and melted paving materials when heat is applied to the bin 26 so as to in fact heat and melt the paving materials disposed therewithin. Surrounding the bin 26 is a heating chamber 38 which is adapted to be heated by means of a heating system 30 which includes one or more burners 32 that receive fuel from a fuel supply container 34. A chimney 40 is fluidically connected to the heating chamber 38 so as to effectively exhaust combustion byproducts from the heating chamber 38, and it is noted that the chimney 40 is likewise fluidically connected to the upper region of the bin 26 by means of a chimney tube 42 so as to likewise exhaust any gaseous by-products effectively trapped within the upper confines of the bin 26. In addition, a cabinet 44 is disposed adjacent to the heating system 30. A vent 46 fluidically connects the heating chamber 38 with the interior of the cabinet 44 when the vent 46 is moved to an open position, and a recirculating pump 60 is disposed within the cabinet 44. The pump 60 is connected to the bin 26 by means of an inflow pipe 62. The output side of the pump 60 comprises an outlet pipe 66 which is fluidically connected to a manifold 68. In turn, a supply line 72, fluidically connected at one end there-of to a heated material dispensing hose 74, is fluidically connected at a second end thereof to a first portion of the manifold 68 through means of a shutoff valve 76, while a recirculation outflow pipe 70, which is fluidically connected at a free end thereof to the bin 26 so as to recirculate the heated fluid back into the bin 26, is fluidically connected at a second end thereof to a second portion of the manifold 68 through means of a differential valve 78. When the heated material is not actually being dispensed, it is recirculated by the pump 60 back to the bin 26. The primary operational problems with a system such as that disclosed within Mertes reside in the fact that the pump 60 is indirectly heated as a result of being located within the interior portion of the cabinet 44, and therefore the degree or level to which the pump 60 is actually heated, in order to effectively preserve the fluidity and/or viscosity of the heated material to predeterminedly desirable values, is difficult to achieve. In addition, as has been noted hereinbefore, when the heated material is not being dispensed as a result of the pump 60 conveying the heated material to the dispensing hose 74, the heated material is being recirculated by the pump 60 back to the bin 26. Accordingly, the pump 60 is effectively always in operation, resulting in excessive wear of the pump components and seals.
With reference now being made to FIG. 2 of the application drawings, which corresponds to FIG. 1 of U.S. Pat. No. 4,859,073 which issued to Howseman, Jr. et al. on Aug. 22, 1989, the disclosed system is another example of a prior art melter and pump assembly which was apparently also state-of-the-art at the time that such patent issued in connection with the supply of similar materials for road paving or sealing operations, however, as can be appreciated from FIG. 2 of the application drawings which corresponds to FIG. 1 of Howseman, Jr. et al., there is disclosed a first embodiment of the system of the melter and pump assembly of Howseman, Jr. et al. which also embodies some fundamental operational problems. In accordance with this first embodiment of the system of Howseman, Jr. et al., which sought to rectify the aforenoted deficiencies of Mertes by eliminating the indirect heating of the pump, as well as eliminating the need for the recirculation of the heated material back to the melter, the material melter and pump assembly of Howseman, Jr. et al. is seen to comprise container 10 within which there is disposed a rotary agitator assembly comprising a rotary motor 18, and a rotary tube 28 which is rotatably driven by means of the motor 18 through means of rotary gears or sprockets 22, 24 interconnected by means of a chain drive 26. Agitator blades 34 are fixedly connected to the rotary tube 28, and a piston pump 46 is axially disposed within the lower end portion of the rotary tube 28 whereby reciprocation of the piston pump 26, relative to a pump ring 40, drives a mixture of the heated material, disposed within the container 10, outwardly from the container 10 and through the central or axial hole defined within the pump ring 40 and through an output dispensing conduit 49. The piston pump 46 is secured to the lower end of a vertical shaft 44, which is coaxially disposed within the rotary tube 28, and the upper end of the vertical shaft 44 is operatively connected to a reciprocating pump drive piston motor 20.
As has been noted hereinbefore, this first embodiment of the assembly of Howseman, Jr. et al. admittedly rectifies the aforenoted problems characteristic of the system of Mertes in that since the pump 46 is effectively disposed in a submerged state within the heated and melted material, the pump 46 will automatically be at the same temperature as the heated and melted material. In addition, there is no need for recirculating the heated or melted material when the pump is not activated for a dispensing operation because the heated or melted material within the pump will never be disposed at a lower temperature which could otherwise cause the heated or melted material to begin to solidify within the pump and cause blockage of the same. However, it is noted that the pump 46 is located within the lower portion of the melter or container 10, and accordingly, if the pump 46 requires servicing, maintenance, or replacement, maintenance personnel must actually climb into and descend downwardly toward the bottom portion of the melter or container 10 in order to gain access to the pump 46 and/or the pump plate 40. This entails dirty, time-consuming, and uncomfortable maintenance procedures to be undertaken.
With reference now being made to FIG. 3 of the application drawings, which corresponds to FIG. 3 of the Howseman, Jr. et al. patent and which discloses a second embodiment of the Howseman, Jr. et al. assembly, the melter or container is disclosed at 54, the pump shaft is disclosed at 50, and the pump is disclosed at 52. It is noted that in lieu of the pump 52 being disposed internally within the melter or container 54 as was the pump 46 of the first embodiment disclosed within FIG. 2 of the application drawings, the pump 52 is fixedly secured to an undersurface or external wall portion of the floor member of the melter or container 54. Therefore, the pump 52 in this embodiment is readily accessible by maintenance personnel, however, a burner, not shown, is adapted to be disposed beneath the pump such that the output of the burner impinges directly upon the pump whereby, over a period of time, the structural integrity of the pump can be compromised. It is also to be noted that the burner, not shown, is likewise disposed beneath the material output dispensing conduit 49 of the first embodiment shown in FIG. 2 of the application drawings such that, in a similar manner, over a period of time, not only is the structural integrity of the material output dispensing conduit 49 likewise to be compromised, but in addition, the material being dispensed can effectively be overcooked or charred.
With reference being made to FIGS. 4A and 4B of the application drawings, which correspond to FIGS. 2A and 2B of U.S. Pat. No. 4,692,028 which issued to Schave on Sep. 8, 1987, this disclosed system is yet still another example of a prior art melter and pump/applicator assembly which was apparently also state-of-the-art at the time that such patent issued in connection with the supply of similar materials for road paving or sealing operations, however, as can be appreciated from FIGS. 4A and 4B of the application drawings which correspond to FIGS. 2A and 2A of the patent to Schave, the system of Schave likewise embodies some fundamental operational problems. In accordance with the system of Schave, a sealant melting chamber is disclosed at 18, and a sealant agitator 34 is rotatably disposed internally of the melting chamber 18. A hydraulic pump 26, which is fluidically connected to a hydraulic fluid reservoir, is also fluidically connected to a two-position diverter valve 30 which can obviously attain two different positions as illustrated within FIGS. 4A and 4B. When the diverter valve 30 is disposed at the position illustrated within FIG. 4A, the hydraulic fluid from hydraulic pump 26, which is fluidically connected to the hydraulic fluid reservoir, is routed through the diverter valve 30 to a hydraulic motor 38 which serves to drive a sealant pump 38 which delivers sealant material to a sealant applicator hose 42. To the contrary, when dispensing of the sealant material is not to be accomplished, the diverter valve 30 is rotated to its other position so as to be disposed at the position illustrated within FIG. 4B whereby the hydraulic fluid from hydraulic pump 26 is routed through diverter valve 30 to hydraulic motor 32 which serves to rotate the sealant agitator 34. The hydraulic fluid is then returned to the hydraulic fluid reservoir. It can therefore be readily appreciated that since both the sealant agitator 34 and the sealant pump 40 are only operated intermittently and alternatively with respect to each other, the sealant disposed within the sealant melting chamber 18 is not continuously mixed and agitated such that the same may not always comprise the desired consistency or viscosity. In a similar manner, since sealant pump 40 is also operated only intermittently or periodically when dispensing of the sealant material is to be achieved, or is not being achieved, and since the sealant pump 40 is disposed externally of the sealant melting chamber 18, the sealant pump 40 will not always be operating at an elevated temperature level such that sealant material within the sealant pump 40 may tend to solidify and thereby clog the sealant pump 40. Still further, it is to be noted that the only connection between the sealant pump 40 and the sealant melting chamber 18 appears to be an outlet pipe, not numbered, which fluidically connects the sealing melting chamber 18 to the sealant pump 40 such that when the sealant pump 40 is actuated by means of the hydraulic motor 38, hot sealant material will flow through the sealant pump 40 and be discharged to the sealant applicator hose 42. When the sealant pump 40 is inoperative, sealant material does not flow through the sealant pump 40, and thus, the temperature level of the sealant pump 40 is not necessarily maintained at the desired elevated temperature level which is a sufficiently high temperature level in order to prevent any solidification of the sealant material within the sealant pump 40 such that clogging of the sealant pump 40 does not occur.
A need therefore exists in the art for a new and improved integral melter and pump system, and a method of making the same, that will effectively address and resolve the aforenoted problems or drawbacks characteristic of the current state of the art and that will achieve the following overall objectives. More particularly, a need exists in the art for a new and improved integral melter and pump system, and a method of making the same, wherein the pump does not operate continuously, either in a pump output supply mode or in a pump recirculation mode, so as not to experience excessive wear, wherein the pump is disposed at a location relative to the melter or material container so as to be sufficiently and constantly/continuously heated to a predetermined temperature level without having its structural integrity compromised, and regardless of whether or not the pump is being operated in its pump output supply mode such that solidification of the material to be dispensed will not solidify and clog the pump, and wherein further, the pump is mounted upon the melter or material container so as to be readily accessible for maintenance repairs or replacement by maintenance personnel.